Externally adjustable pipe orifice assembly

Abstract

A coal pulverizer is connected to the burner nozzles of a tangentially-fired furnace with conduits of varying lengths through which air-entrained coal is supplied for combustion within the furnace. An externally adjustable orifice assembly is mounted in each connecting conduit to equalize the flow of coal/air through the conduits to nozzles in the windboxes. Each orifice assembly comprises pivotable plates which move transverse the axis of the conduit to form an orifice in controlling the coal/air flow.

I claim: 
     
       1. In a system for controlling the air-entrained coal flowing from a pulverizer to each fuel nozzle mounted within a windbox of a tangentially-fired furnace, including. a conduit connected between the pulverizer and fuel nozzles mounted in each windbox,   a bracket mounted between two sections of the conduit,   a plurality of abrasion-resistant plate segments and each having a configuration of an arc and pivoted eccentrically from the bracket toward and away from the axis of the conduit.   and screws operative from external the conduit and mounted in threaded engagement with the bracket and each screw bears upon the edge of a plate segment to determine its pivoting toward or away from the axis of the conduit in establishing an orifice-like pressure drop developing restrictions to air-entrained coal flowing through the conduit so as to provide a means for selective control of the flow through the conduit.